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Scorpion envenomation as a risk factor for development of dilated cardiomyopathy
T Sundararaman1, M Olithselvan, K R Sethuraman
1Dept. of Medicine, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India.
Insights
A history of scorpion stings significantly increases the risk of developing idiopathic dilated cardiomyopathy. Even after recovery, scorpion envenomation may lead to long-term heart issues.
Area of Science:
- Cardiology
- Toxicology
- Epidemiology
Background:
- Scorpion envenomation can cause acute myocarditis and temporary left ventricular dysfunction.
- Idiopathic dilated cardiomyopathy (IDCM) has multifactorial causes, but specific etiological links are often unclear.
- The role of scorpion stings in the long-term development of IDCM has not been previously established.
Purpose of the Study:
- To investigate the association between a history of scorpion envenomation and the development of idiopathic dilated cardiomyopathy.
- To explore other potential risk factors for IDCM, including socio-economic status, lifestyle choices, and other environmental exposures.
Main Methods:
- A case-control study design was employed to assess risk factors for IDCM.
- Cases of IDCM were compared against two control groups: age- and sex-matched inpatients and spouse/relatives.
- Statistical analysis was performed to determine the association between various factors and IDCM.
Main Results:
- Scorpion envenomation emerged as the only significant risk factor associated with IDCM.
- A history of scorpion sting showed a significantly elevated odds ratio (8.01-8.33) for developing IDCM compared to both control groups.
- Other studied factors like smoking, alcoholism, and rural habitation did not demonstrate a significant association with IDCM.
Conclusions:
- A history of scorpion envenomation is a significant risk factor for the subsequent development of idiopathic dilated cardiomyopathy.
- Sub-clinical cardiac deficits following scorpion stings may predispose individuals to cardiomyopathy later in life.
- This finding supports the hypothesis linking catecholamine excess, potentially triggered by scorpion venom, to cardiac dysfunction and cardiomyopathy development.
Objectives:
Though scorpion envenomation is known to lead to acute myocarditis and a reversible decrease in left ventricular function, it has not been implicated as an etiological factor in idiopathic dilated cardiomyopathy. We studied the association of idiopathic dilated cardiomyopathy with a history of scorpion sting as well as with socio-economic status, history of smoking and alcoholism, rural habitation, and history of snake bites.
Methods:
Consecutive cases of idiopathic dilated cardiomyopathy were recruited for this study: The association with putative risk factors was studied using a case-control study design with two sets of controls. One set of controls were age and sex matched inpatients selected at random, the other set of controls were spouse, or if not available, a close relative, ordinarily resident with the patient.
Results:
On analysis, none of the factors except scorpion envenomation had a significant association. A past history of scorpion envenomation had an adjusted odds ratio of 8.01 (3.55-18.06) when compared to one set of controls and an odds ratio of 8.33 (6.55-10.59) when compared to the second group of controls.
Conclusions:
Our study indicates that a history of scorpion envenomation acts as a risk factor for the subsequent development of idiopathic dilated cardiomyopathy. Despite an apparently complete recovery from a scorpion sting, many patients probably retain sub-clinical deficits that predispose to the development of cardiomyopathy later in life, when other factors get added on. The known association of cardiomyopathy with catecholamine excess in experimental situations in animal studies, and in other disease states in humans, supports this hypothesis.